Recumbent bike system and method

ABSTRACT

A recumbent bike is disclosed that has a larger portion of its crank cycle, compared with conventional approaches, in which a relatively high level of power can be inputted. Consequently, potential exists for a user to experience a high cardiovascular load with less fatigue or other muscular difficulties. Improvements over conventional approaches are achieved, among other things, through enhanced seat positioning relative to the crank axis of the bike.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention is directed generally to bikes and, more particularly, to recumbent bikes including recumbent exercise bikes.

2. Description of the Related Art

Bikes are useful for exercise and transportation purposes. In particular, both mobile and stationary bikes are frequently used for cardiovascular exercise since large muscle groups are used, which can put significant load on the cardiovascular system of an individual. A given amount of work that can be input into the bike mechanism by an individual will directly affect the amount of load that can be put on the cardiovascular system.

As is commonly known, to input work into a bike, force is applied to pedals to turn a crank. For a given power level to be input into a bike, in an ideal case, a steady force would be applied to the pedals throughout the entire 360° of the crank cycle so that the degree of force necessary at any time through the crank cycle could be kept to a minimum. Reduced required forces results in less muscle fatigue and greater levels of power that can potentially be inputted into a bike. Greater levels of power can potentially result in greater cardiovascular load that can be applied to potentially achieve more efficient cardiovascular training and higher levels of cardiovascular fitness.

Unfortunately, conventional bikes have significant portions of their crank cycles in which power cannot be as effectively inputted into the bikes compared with other portions of their crank cycles. This uneven level of power input capacity found in the conventional crank cycles can result in higher levels of fatigue and/or reduced potential cardiovascular load. Thus, improvements to allow for a relatively high power input capacity over a larger portion of the crank cycle could be desirable.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING(S)

FIG. 1 is an isometric view of a recumbent bike according to present invention.

FIG. 2 is a side elevational view of the recumbent bike of FIG. 1 with its seat in a first tilt position.

FIG. 3 is a side elevational view of the recumbent bike of FIG. 1 with its seat in a second tilt position.

FIG. 4 is a side elevational view of the recumbent bike of FIG. 1 with its seat in a forward rail position.

FIG. 5 is a side elevational view of the recumbent bike of FIG. 1 with its seat in a mid-rail position.

FIG. 6 is a side elevational view of the recumbent bike of FIG. 1 with its seat in a rear rail position.

FIG. 7 is a side elevational view of a schematic of a representative human showing various joints and links.

FIG. 8 is a side elevational view of a schematic of the representative human of FIG. 7 showing various muscle groups.

FIG. 9 is a table of anthropomorphic data.

FIG. 10 is a side elevational view a schematic of the recumbent bike of FIG. 1 with a portion of the representative human engaged therewith.

FIG. 11 is a side elevational view of a schematic of the recumbent bike of FIG. 1 with a portion of the representative human engaged therewith, showing forces being applied by relevant muscle groups.

FIG. 12 is a side elevational view of a schematic of the recumbent bike with a portion of the representative human engaged therewith showing a range of positions where use of the gluteus muscle group is favored.

FIG. 13 is a side elevational view of a schematic of the recumbent bike with a portion of the representative human engaged therewith showing a range of positions where power input in reduced.

FIG. 14 is a side elevational view of a schematic of the recumbent bike showing seat positioning detail.

FIG. 15 is a table having seat positioning detail related to FIG. 14.

FIG. 16 is an isometric view of an alternative version of the recumbent bike of FIG. 1.

FIG. 17 is a side elevational view of the recumbent bike of FIG. 16 with its seat in a first tilt position.

FIG. 18 is a side elevational view of the recumbent bike of FIG. 16 with its seat in a second tilt position.

DETAILED DESCRIPTION OF THE INVENTION

As will be discussed in greater detail herein, a recumbant bike is disclosed that has a larger portion of its crank cycle, compared with conventioral approaches, in which a relatively high level of power can be inputted. Consequently, potential exists for a user to experience a high cardiovascular load with less fatigue or other muscular difficulties. Improvements over conventional approaches are achieved, among other things, through enhanced seat positioning relative to the crank axis of the bike. Other advantages will become apparent in the following discussion.

A recumbant bike 100 is shown in FIG. 1 as having a base portion 102 and a seat 104. The base portion 102 includes pedals 105 mechanically coupled to a load mechanism (not shown) such as a generator, friction brake, flywheel fan, wheel contacting a weight bearing surface such as the ground or road, or other such load mechanism. The pedals 105 are rotatable about a crank axis 106 through crank or shafts 107. The base portion 102 further includes support legs 108 for resting the bike 100 on a floor, a monitor 110 for supplying exercise status to a user (not shown), and a rail 112 for supporting the seat 104.

The seat has a seat bottom 114 and a seatback 116. The seat 104 further includes a support portion 118 for mechanical engagement with the rail 112 such that the position of the seat along the rail 112 can be adjusted. The seat 104 has a tilt lever 120 to adjust a tilt angle 123, shown in FIG. 2, between the seat bottom 114 and the rail 112 by releasing a locking mechanism (not shown) to allow pivoting of the seat about a pivot 124. As an example of tilt adjustment of the seat 104, the tilt angle 123 as shown in FIG. 3 is larger than the tilt angle shown in FIG. 2.

The support portion 118 of the seat 104 further includes a rail adjustment lever 127, shown in FIG. 4, to adjust and secure seat position along the rail 112. Examples of adjustment of the position of the seat 104 along the rail 112 are shown in FIGS. 4-6 in which the seat is in a forward rail position (FIG. 4), a mid-rail position (FIG. 5), and a rear rail position (FIG. 6). To adjust rail postion of the seat 104, the rail adjustment lever 127 is used to unlock the support portion 118 from fixed engagement with the rail 112 to allow sliding of the seat longitudinally along the rail. The rail adjustment lever 127 is then used to lock the support portion 118 in fixed engagement with the rail 112 once a desired longitudinal rail position of the seat has been achieved. A seat reference location 126 is shown and will be used below to describe enhanced positioning of the seat 104 relative to the crank axis 106. As depicted, the seat reference location 126 can be located where surface planes of the seat bottom 114 and the seatback 116 intersect. The seat 104 is shown as being hard (i.e. nondeforming). For other implementations, the seat 104 can be softer so that the seat bottom 114 and/or the seatback 116 may be deformed somewhat when occupied by a user. The location of the seat reference location 126 should be adjusted for these softer seat implementations to take into account particular deformity caused to the seat bottom 114 and/or the seatback 116 when occupied. As depicted in FIG. 4, the bike 100 rests on a floor 128. In this depiction, a floor angle 129 exists between the rail 112 and the floor 128.

A schematic depiction of a representative human 130 is shown in FIG. 7 illustrating various portions of the human involved with use of the bike 100. The human 130 includes a hip joint 132, a knee joint 134, an ankle joint 136, and a ball of the foot 138. The human 130 further includes a back link 140 extending from the hip joint 132, a thigh link 142 extending between the hip joint and the knee joint 134, a lower leg link 144 extending between the knee joint and the ankle joint 136, and a foot link 146 extending between the ankle joint and the ball of the foot 138. Hip angle 147, knee angle 148 and ankle—foot angle 150 can be used to describe position of the human 130. Further depictions include a first spacing 152 to approximate distance between the hip joint 132 as seated in the seat 104 and the seat bottom 114. A second spacing 154 approximates distance between the hip joint 132 as seated in the seat 104 and the seatback 116.

The human 130 is shown schematically in FIG. 8 to include secondary muscle groups such as hip flexor muscles 156 and hamstring muscles 158. The hip flexor muscles extend between the back link 140 and the thigh link 142 around a forward portion of the hip joint 132. Hamstring muscles 158 extend between the thigh link 142 and the lower leg link 144 around a rearward portion of the knee joint 134.

Primary muscle groups shown include quadricep muscles 160 and gluteus muscles 162. The quadricep muscles 160 extend between the thigh link 142 and the lower leg link 144 around a forward portion of the knee joint 134. The gluteus muscles 162 extend between the back link 140 and the thigh link 142 around a rearward portion of the hip joint 132.

An anthropomorphic data table shown in FIG. 9 contains commonly known measurements relevant to the bike 100 and used in describing various portions of the male and female population. In this table data is shown for 1% male, 50% male, 99% male, 1% female, 50% female, and 99% female, where 1% female is smallest and 99% male is largest. The nomenclature used for the anthropomorphic data is commonly known. For instance, the 1% female data means that all but 1% of the female population have measurements at least of that found in the anthropomorphic data table. Implementations of the bike 100 are directed toward use by a group including the 1% female and the 99% male and all those of size in between.

The bike 100 incorporates the following understanding of how the human 130 interacts with the bike as depicted in schematic representations of the bike and the human shown in FIGS. 10-13. During operation, the human 130 is seated in the bike 100 as shown in FIG. 10 to input power into the bike by pushing on the pedals 105. A power stroke portion of the crank cycle in which a substantial portion of power from the human is inputted to the bike is between an initial power stroke leg position 170 and a final power stroke leg position 172 in which both positions are defined by reference line 174 extending from the hip joint 132 through both positions of the pedal 105 as rotation occurs in a clockwise direction 176 as viewed in FIG. 10.

The primary muscle groups used in pedaling are the quadricep muscles 160 for extending the knee joint 134 in the direction of arrow 178 in FIG. 11 and the gluteus muscles 162 for extending the hip joint 132 in the direction of arrow 180. Both the quadricep muscles 160 and the gluteus muscles 162 provide a substantial amount of their contribution to power input during the power stroke portion of the crank cycle. Experienced riders are able to use other muscles as well to input additional amounts of power but to a smaller extent.

Forces exerted on the knee joint 134 can be quite harmful if excessive. It has been found that the final power stroke leg position 172 with the knee angle 148, as shown in FIG. 11, between 150° and 160° can reduce stress on the knee joint 134 while allowing for efficient power transfer from the human 130 to the bike 100 during the power stroke portion of the crank cycle. When the knee angle 148 exceeds approximately 160° at the final power stroke leg position 172, the quadricep muscles 160 start losing their mechanical advantage for extending the knee joint 134 so must be aided by weaker knee stabilizer muscles. Consequently, this inefficient use of the quadricep muscles 160 can result in undesirable wear to the knee joint 134.

Another aspect of pedaling comfort and efficiency regards the hip angle 147. It has been found that the gluteus muscles 162 can best be used to generate power to the bike 100 when the hip angle 147 is between 100° degree position 190 for leg position 184 and 120° degree position 188 for leg position 186. This suggests that the gluteus muscles 162 would be better utilized if the hip angle 147 can be maintained between 100° and 120° during a substantial amount of the power stroke portion of the crank cycle (such as at least 75% or at least 85% of the power stroke portion of the crank cycle) as shown in FIG. 12.

An initial part of the power stroke from the initial power stroke leg position 170 to an intermediary power stroke leg position 192, as shown in FIG. 13, is least efficient in allowing power input from the human 130 to the bike 100. During this initial power stroke portion, either power is inputted almost exclusively by the quadricep muscles 160 or momentum simply furthers the rotation. After the intermediary power stroke leg position 192 is reached, both the quadricep muscles 160 and the gluteus muscles 162 are used through the remainder of the power stroke portion of the crank cycle.

In summary, three factors described above can contribute to increase power input to the bike 100 and/or cardiovascular load on the human 130 while reducing fatigue, injuries or other physical problems compared with conventional approaches. These factors are providing the desirable range of values for the knee angle 148 of between 150° and 160° at the final power stroke leg position 172, increasing that portion of the power stroke that the desirable range of values is maintained for the hip angle 147 between 100° and 120°, and decreasing the extent of the initial power stroke portion that solely the quadricep muscles 160 and/or momentum are used to continue rotation. An additional fourth factor is that it is more beneficial for the human 130 to push lower on the seatback 116 toward the position of the seat bottom 114 rather than high up on the seatback. In this manner, reaction forces from pedaling are applied more directly into the seatback 116. If forces are applied to high on the seatback 116, the human 130 tends to be lifted out of the seat 104, which results in less efficient application of power from the human to the bike 100.

The bike 100 addresses these four factors by providing a unique position for the seat 104 in relation with the crank axis 106. In particular, this position for the seat 104 is described in terms of the positioning of seat reference location 126 with respect to the crank axis 106. FIG. 14 shows further detail regarding how implementations of the bike 100 position the seat reference location 126 with respect to the crank axis 104.

The bike 100 is constructed to position the rail 112 such that an illustrative line 200 can extend from the crank axis 106 at an angle 202 with respect to the rail. Furthermore, an illustrative line 204 can extend from the reference point 126 of the seat 104 and parallel to the illustrative line 200. When an illustrative line 206 extends perpendicularly from the illustrative line 200 at the position of the crank axis 106 it perpendicularly intersects the illustrative line 204. The distance along the illustrative line 204 between the reference point 126 and the illustrative line 206 defines the length of the illustrative line 204. The distance between the illustrative line 200 and the illustrative line 204 along the illustrative line 206 defines the length of the illustrative line 206.

For implementations of the bike 100 that address the four factors discussed above for the ranges of the human 130 from the 1% female to the 99% male according to the factors described in the table of FIG. 9, the length of the illustrative line 206 is between 4 inches and 6 inches for a particular range of lengths of the illustrative line 204 required to accommodate the human 130 in the 1% female to the 99% male group. Other implementations of the bike 100 may be targeted to other groups of the human 100 such that the length of the illustrative line 206 need only be maintained between 4 inches and 6 inches for a smaller range of lengths of the illustrative line 204 than the range of lengths for the illustrative line 204 required for the 1% female to 99% male group discussed above. Other dimensions shown in FIG. 14 include an angle 208 between the seat bottom 114 and the illustrative line 204 A depicted implementation of the bike 100 allowed positioning of the seat 104 along the rail 112 to include accommodation for a 1% female, a 50% male, and a 99% male, as shown in FIG. 15, to stay within the beneficial 4 to 6 inch range discussed above for the length of the illustrative line 206 while the angle 202 was at 3° and the angle 208 was at 5°. In the implementation of the bike 100 depicted by the data found in FIG. 15, the length of the illustrative line 206 actually stayed within 0.5 inches of 5 inches for a length of the illustrative line 204 of 27.4 inches to 33.5 inches, which is some instances may offer an additional degree of benefit compared with the benefits conferred by staying within the broader range of 4 to 6 inches for the length of the illustrative line 206.

Other dimensions shown in FIG. 14 include an illustrative line 210 extending from the hip joint 132 and parallel to the illustrative line 200, an angle 212 between the illustrative line 200 and the floor 128. In some implementations of the bike 100, the value of the angle 212 can be 0° so that the value of the angle 129 is equal to the value of the angle 202. In other implementations of the bike 100, the angle 212 has a nonzero value.

Further dimensions illustrated in FIG. 14 include an angle 214 between the thigh link 142 when at the final power stroke leg position 172 and the illustrative line 210, and an angle 216 between the seat back 116 and seat bottom 114. For depicted implementations, the angle 214 had a value of approximately 173°, such as between 170° and 176°, which may contribute to some extent to the beneficial factors mentioned above. The angle 216 for some implementations of the bike 100 has a value of 113° and is considered to offer some contribution to maintaining for the hip angle 147 between 100° and 120° over a larger portion of the power stroke.

As discussed above, the tilt angle 123 of the seat 104 can be adjusted; consequently, the angle 208 can change. Implementations of the seat 100 are constructed to allow for predetermined ranges of the angle 208 while still maintaining the value of the length of the illustrative line 206 within the 4 to 6 inch range over the required range of lengths of the illustrative line 204 for the ranges of sizes for a particular group of the humans 130. It has been found that providing adjustment of the tilt angle 123 allows for adjustment of how much the quadricep muscles 160 are used compared with how much the gluteus muscles 162 are used to input power to the bike 100. Adjustment of the tilt angle 123 can be done during exercise, for instance when one muscle group requires some relief compared with another muscle group. The tilt angle 123 can be significantly increased to accommodate those of large girth or for others who desire such positioning of the seat 104 since the bike 100 is constructed to still maintain the desired range of length for the illustrative line 206. In some implementations the tilt angle 123 can be adjusted from 0° to 20° in five degree increments.

Regarding decreasing of the extent of the initial power stroke portion that solely the quadricep muscles 160 and/or momentum are used to continue rotation, in one particular implementation a reduction of approximately 25% was observed from approximately 60°, for a conventional approach, to 45° for the bike 100. For a given amount of work to be inputted, applying work over a longer portion of the pedal stroke reduces muscle forces needed to be produced. Less muscle strain can have beneficial consequences such as a decreased likelihood that the legs fatigue before the cardiovascular system has been fully exercised and a decreased likelihood of injuries due to repetitive motion stresses. The initial power stroke portion that solely the quadricep muscles 160 and/or momentum are used to continue rotation occurs from the beginning of the power stroke through a pedal angle which causes the hip angle 147 to begin increasing. By decreasing the amount of the stroke that is done exclusively with the knee extensor (the quadriceps muscles 160) stress on the knee joint 134 is decreased. The longer force is supplied by the quadricep muscles 160 alone, the more knee strain results. If a person uses the momentum of their leg until the leg begins to involve the gluteus muscles 160, the person must provide all of the force to overcome frictional resistance plus enough to carry it through this inefficient coasting portion of the power stroke. By reducing this inefficient portion of the power stroke, the primary muscle groups are involved over a longer duration thereby decreasing the forces needed to exert the same work and thereby decreasing undesirable impulse forces exerted on the body resulting from applying undesirably large forces during a relatively short duration of the crank cycle.

An alternative version of the implementation of the recumbent bike 100 is shown in FIGS. 16-18.

From the foregoing it will be appreciated that, although specific embodiments of the invention have been described herein for purposes of illustration, various modifications may be made without deviating from the spirit and scope of the invention. For instance, other implementations of the bike 100 can have different configurations for the rail 112 or other support mechanisms of the seat 104 with or without rails and still maintain the length of the illustrative line 206 within the desired range discussed above over the required range of lengths for the illustrative line 204 for a given group of the humans 130. Accordingly, the invention is not limited by only those implementations described in detail herein. 

1. A system comprising: a base portion including a rail and pedals, the pedals rotatable about a crank axis; and a seat moveably coupled to the rail, the seat including a bottom and a back, the intersection of the bottom and the back forming a seat reference location, the seat spaced from the crank axis so that when a first illustrative line is extended from the crank axis, and a second illustrative line is extended from the seat reference location, the second illustrative line being parallel to the first illustrative line, the first illustrative line and the second illustrative line are spaced from one another between 4 inches and 6 inches.
 2. The system of claim 1 wherein the seat is spaced from the crank axis so that when a third illustrative line is extended perpendicular to the first illustrative line from the crank axis to an intersection point of the third illustrative line and the second illustrative line, the seat reference location is spaced from the intersection point between 27.4 inches and 33.5 inches.
 3. The system of claim 1 wherein the seat is sufficiently deformable to allow for differences in location of the seat reference location between when the seat is unoccupied and occupied by a user with the first illustrative line and the second illustrative line spaced from one another between 4 inches and 6 inches.
 4. The system of claim 1 wherein the back of the seat and the bottom of the seat are positioned with respect to each other at an angle of approximately 113°.
 5. The system of claim 4 wherein the first illustrative line and the second illustrative line are spaced from one another between 4.5 inches and 5.5 inches.
 6. The system of claim 1 wherein the rail is positioned at an approximate 3° angle from the first illustrative line.
 7. The system of claim 6 wherein the rail is positioned at an approximate 3° angle from a floor surface.
 8. The system of claim 1 wherein the bottom of the seat is positioned at an approximate 5° angle from the second illustrative line.
 9. The system of claim 1 for a user with a hip joint and a thigh link, the seat being positioned with respect to the crank axis so that when the user is seated in the seat adjacent the bottom and back of the seat with the user's foot contacting the pedal, the user has an initial power stroke leg position with the pedal at a first pedal position and a final power stroke leg position with the pedal at a second pedal position, the first pedal position being substantially in-line between the hip joint of the user and the second pedal position, when a fourth illustrative line is extended from the hip joint of the user, the fourth illustrative line being parallel to the first illustrative line, and when the pedal is at the second pedal position, an angle between the thigh link and the fourth illustrative line is between 170° and 176°.
 10. The system of claim 9 wherein the seat is positioned with respect to the crank axis so that when the pedal is in the second pedal position, the angle between the thigh link and the fourth illustrative line is approximately 173°.
 11. A system for a human user having a knee joint, a hip joint, a back link extending from the hip joint, a thigh link extending between the hip joint and the knee joint, a lower leg link extending from the knee joint, a hip angle being at the hip joint between the back link and the thigh link, a knee angle being at the knee joint between the thigh link and the lower leg link, and a foot, the system comprising: a base portion including a pedal and a crank axis, the pedal rotatable about the crank axis; and a seat coupled to the base portion, the seat including a bottom, a back, and being spaced a distance from the crank axis so that when the user is seated in the seat adjacent the bottom and back of the seat with the user's foot contacting the pedal, the user has an initial power stroke leg position with the pedal at a first pedal position and a final power stroke leg position with the pedal at a second pedal position, the first pedal position being substantially in-line between the hip joint of the user and the second pedal position, so that the knee angle of user is substantially between a range of 150° and 160° when the pedal is in the second pedal position, and so that the hip angle of the user is between a range of 100° and 120° during at least 75% of a direction of travel of the pedal between the first pedal position and the second pedal position.
 12. The system of claim 11 wherein the seat is spaced the distance from the crank axis so that the hip angle of the user is between a range of 100° and 120° during at least 85% of a direction of travel of the pedal between the first pedal position and the second pedal position.
 13. The system of claim 11 further comprising a rail with the seat being coupled thereto.
 14. A method comprising: providing a seat with a bottom and back intersecting to form a seat reference location; providing pedals; providing a crank axis about which the pedals rotate; and positioning the seat with respect to the crank axis so that when a first illustrative line is extended from the crank axis, and a second illustrative line is extended from the seat reference location, with the second illustrative line parallel to the first illustrative line, the first illustrative line and the second illustrative line are spaced from one another between 4 inches and 6 inches.
 15. The method of claim 14 wherein the positioning the seat with respect to the crank axis further includes positioning the seat with respect to the crank axis so that when a third illustrative line is extended perpendicular to the first illustrative line from the crank axis to an intersection point of the third illustrative line and the second illustrative line, the seat reference location is spaced from the intersection point between 27.4 inches and 33.5 inches.
 16. The method of claim 14 wherein the positioning the seat with respect to the crank axis further includes positioning the seat with respect to the crank axis to allow for differences in location of the seat reference location when the seat is unoccupied and occupied by a user so that the first illustrative line and the second illustrative line are spaced from one another between 4 inches and 6 inches.
 17. The method of claim 14 further including positioning the back of the seat and the bottom of the seat with respect to each other at an angle of approximately 113°.
 18. The method of claim 17 wherein the positioning the seat with respect to the crank axis further includes positioning the seat with respect to the crank axis so that the first illustrative line and the second illustrative line are spaced from one another between 4.5 inches and 5.5 inches.
 19. The method of claim 14 further including positioning a rail slidably engaged with the seat at an approximate 3° angle from the first illustrative line.
 20. The method of claim 19 wherein positioning the rail includes positioning the rail at an approximate 3° angle from a floor surface.
 21. The method of claim 14 further including positioning the bottom of the seat at an approximate 5° angle from the second illustrative line.
 22. The method of claim 14 for a user with a hip joint and a thigh link, wherein positioning the seat with respect to the crank axis further includes positioning the seat with respect to the crank axis so that when the user is seated in the seat adjacent the bottom and back of the seat with the user's foot contacting the pedal, the user has an initial power stroke leg position with the pedal at a first pedal position and a final power stroke leg position with the pedal at a second pedal position, the first pedal position being substantially in-line between the hip joint of the user and the second pedal position, when a fourth illustrative line is extended from the hip joint of the user, the fourth illustrative line being parallel to the first illustrative line, and when the pedal is at the second pedal position, an angle between the thigh link and the fourth illustrative line is between 170° and 176°.
 23. The method of claim 22 wherein positioning the seat with respect to the crank axis further includes positioning the seat with respect to the crank axis so that when the pedal is in the second pedal position, the angle between the thigh link and the fourth illustrative line is approximately 173°.
 24. A method for a human user having a knee joint, a hip joint, a back link extending from the hip joint, a thigh link extending between the hip joint and the knee joint, a lower leg link extending from the knee joint, a hip angle being at the hip joint between the back link and the thigh link, a knee angle being at the knee joint between the thigh link and the lower leg link, and a foot, the method comprising: providing a base portion including a pedal and a crank axis, the pedal rotatable about the crank axis; providing a seat coupled to the base portion, the seat including a bottom and a back, and locating the seat a distance from the crank axis so that when the user is seated in the seat adjacent the bottom and back of the seat with the user's foot contacting the pedal, the user has an initial power stroke leg position with the pedal at a first pedal position and a final power stroke leg position with the pedal at a second pedal position, the first pedal position being substantially in-line between the hip joint of the user and the second pedal position, so that the knee angle of user is substantially between a range of 150° and 160° when the pedal is in the second pedal position, and so that the hip angle of the user is between a range of 100° and 120° during at least 75% of a direction of travel of the pedal between the first pedal position and the second pedal position.
 25. The method of claim 24 wherein locating the seat includes locating the seat the distance from the crank axis so that the hip angle of the user is between a range of 100° and 120° during at least 85% of a direction of travel of the pedal between the first pedal position and the second pedal position. 